Mosin Nagant Aftermarket Parts

of the 12 - 91-30 and 6 T53 I bought all had a stamped sheet metal latch piece. I bought 2 magazines that are complete and they have what appears to be milled latch pieces. 1 came on finn no jam with tula hammer stamp and 1 came with Izhevsk stamp. does anyone know what they are? they do function better than stamped piece ones.